Hirsch Arthur, Lacour Stéphanie P
Bertarelli Foundation Chair in Neuroprosthetic Technology Laboratory for Soft Bioelectronic Interfaces Institute of Microengineering Institute of Bioengineering Centre for Neuroprosthetics École Polytechnique Fédérale de Lausanne (EPFL) 1202 Geneva Switzerland.
Adv Sci (Weinh). 2018 Aug 9;5(10):1800256. doi: 10.1002/advs.201800256. eCollection 2018 Oct.
Several methods are proposed to manipulate and pattern liquid metal films into elastic conductors but all lack precise control over the film thickness and roughness, thereby limiting its uniformity, stability, and reproducibility. Here, an approach relying solely on wetting phenomena is proposed to produce smooth film of liquid gallium (Ga) on extended surface areas with controlled thickness and electrical properties. The surface chemistry and topography of silicone rubber (poly(dimethylsiloxane)) is engineered with microstructured pillars and gold precoating layer to produce Ga superlyophilic substrates. Physical vapor deposition of Ga on such substrates leads to the formation of smooth and homogeneous films by imbibition of the surface topography rather than coalescence and formation of Ga drops. By capillarity, Ga accumulates in between the pillars up to their top surface, forming a smooth film with a root mean square roughness (Rq) smaller than 100 nm. The wetting conditions and electromechanical properties of the resulting films are compared based on the selection of the microtexture patterns and a model of the film sheet resistance as a function of the texture geometrical parameters is established.
人们提出了几种方法来将液态金属膜加工成弹性导体并形成图案，但所有方法都缺乏对膜厚度和粗糙度的精确控制，从而限制了其均匀性、稳定性和可重复性。在此，我们提出了一种仅依赖于润湿性现象的方法，以在具有可控厚度和电学性质的大面积表面上制备光滑的液态镓（Ga）膜。通过微结构柱和金预涂层对硅橡胶（聚二甲基硅氧烷）的表面化学和形貌进行设计，以制备Ga超亲液性基底。在这种基底上物理气相沉积Ga会通过表面形貌的吸液作用而不是Ga液滴的聚结和形成，从而形成光滑且均匀的膜。通过毛细作用，Ga在柱之间积聚直至其顶面，形成均方根粗糙度（Rq）小于100 nm的光滑膜。基于微观纹理图案的选择，比较了所得膜的润湿条件和机电性能，并建立了膜薄层电阻作为纹理几何参数函数的模型。
